Device for controlling the movement of the printing head in printers

ABSTRACT

A device for controlling the movement of the printing head in printers comprising an operating lever pivotably mounted on the printing head and a cam plate arranged along the path for movement of the printing head and having cam portions engageable with said operating lever in order to move the printing head so that the printing head is pushed against the platen only in the printing stroke, and arranged to simplify the construction and to facilitate designing and machining works of component parts.

Furman et al 197/1 R X O United States Patent 1 1 [111 3,881,587 Okabe May 6, 1975 [54] DEVICE FOR CONTROLLING THE 2,851,141 9/1958 Kistner 197/1 R MOVEMENT OF THE PRINTING HEAD IN 3,300,017 l/1967 Yazejian et al. 197/1 R PRINTERS 3,313,389 4/1967 Cralle, Jr. 197/82 3,592,311 7/1971 Chou et a1. 197/1 R [75] Inventor: Katsuhiko Okabe, Tokorozawa,

Japan Primary ExaminerClifford D. Crowder [73] Assignee: Kabushiki Kaisha Koparu, n y, g or Firmcushman, Da y &

Tokyo-to, Japan Cushman [22] Filed: Oct. 29, 1973 21 Appl. No.: 410,559 [571 ABSTRACT A device for controlling the movement of the printing [3O] Fnreign Application Priority Data head in printers comprising an operating lever pivotably mounted on the printing head and a cam plate ar- Nov. 1, 1972 Japan 47-126456[U] ranged along the path for movement of the Printing [521 U S Cl 197 197/16 197MB head and having cam portions engageable with said [51] 3/20 operating lever in order to move the printing head so [58] Fie'ld l that the printing head is pushed against the platen only 1 in the printing stroke, and arranged to simplify the construction and to facilitate designing and machining [56] References Cited works of component parts.

1 Claim, 1 Drawing Figure DEVICE FOR CONTROLLING THE MOVEMENT OF THE PRINTING HEAD IN PRINTERS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer which is adapted to print by reciprocating a printing head along a platen and. more particularly. to a device for controlling the movement of the printing head in printers arranged to push the printing head for printing during ad- I vancing movement of the printing head and to release SUMMARY OF THE INVENTION The primary object of the present invention is to provide a device for controlling the movement of the printing head in printers of simple construction for which it is easy to design and machine the component parts.

This object can be attained, according to the present invention, by pivotably mounting an operating lever which can be rotated in only one direction on a swingable printing head, engaging said operating lever with a cam plate arranged along the path for movement of the printing head, and controlling the movement of the printing head by said cam plate through said operating lever. Said cam plate has a cam portion serving to push the printing head to the platen and a cam portion serving to release the printing head from the platen. Besides, the printing head has a spring for pushing the printing head toward the platen.

BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing shows a perspective view of the major part of the device for controlling the movement of the printing head in printers according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT On the drawing, reference numeral l designates a pair of guide shafts supported by a body frame of a printer which is not illustrated here. Numeral 2 designates a head base slidably mounted on guide shafts l and reciprocated by a mechanism not illustrated here. Said head base has a pair of upright arms 2:: and a pin 211 secured to the bottom thereof. Numeral 3 designates a printing head having a printing portion 3a and protruberances 3b and 30. As the protruberance 3b is pivotably mounted to arms 2a by a shaft 4, the printing head 3 is pivotably supported by the head base 2 for movement between a first printing position and a second non-printing position. Numeral 5 designates a first spring provided between the pin 2b and printing head 3 and urging the printing head clockwise. Numeral 6 designates an operating lever pivotably mounted on the printing head 3 and having a bent portion 6a which engages with the side portion of the printing head. Numeral 8 designated a pin secured to the operating lever 6. Numeral 9 designates a second spring wound around a shaft 7, both ends of said spring 9 being respectively hooked to the pin 8 and the side portion of the printing head 3. The spring 9 urges the operating lever 6 clockwise. Numeral l0 designates a cam plate attached to the body frame in parallel with guide shaftsl and hav. ing a cam surface 10A to be engaged with the pin 8. The cam surface 10A comprises a high portion 1011, low portions 10b and 10b, step portion and slope portion 10d. The printing portion 3a of the printing head 3 is facing the platen not illustrated here through a paper to be printed and the drawing showsthe condition that the printing portion 3a is pushed against the platen. i.e., the condition that the printing head 3 is held in the printing position.

Operation of the device is as described below. When the head base 2 is moved rightward by the mechanism not illustrated here and the pin 8 reaches the step portion 101' of the cam plate 10, the printing head 3 is turned clockwise around the shaft 4, by tension of the spring 5, so that the pin 8 is dropped from the high portion 10a of the cam surface 10A to the low portion 10b. As a result, the printing portion 3a is released from the platen and the printing head 3 is turned to the non-printing position. The shaft 7 is designed so that it comes to a position higher than the high portion 10a of the cam surface 10A when theprinting head 3 is in said non-printing position. I

When the head base 2 is then moved leftward from the above condition, the operating lever 6 turned counterclockwise around the shaft 7, against the force of the spring 9, by means of the step portion 10c and serves to pull up the pin 8 from the low portion 10b of the cam surface 10A to the high portion 10a.

Thus, the pin 8 is placed on the high portion 10a of the cam surface 10A and is moved leftward sliding along the high portion 104:. In this case, the printing head 3 is moved leftward with the printing portion 3a kept as released from the platen.

When the pin 8 reaches the low portion 10b of the cam surface 10A passing through the slope portion I 10d, the operating lever 6 is turned clockwise by tension of the spring 9 until the bent portion 6a contacts the side face of the printing head 3, though the printing head 3 is kept as held in the non-printing position.

When the head base 2 is moved rightward again for the next printing operation from the above condition, the pin 8 is first raised from the low portion 10b of the cam surface 10A to the high portion 10a passing through the slope portion 10d. At that time, the operating lever 6 is subjected to a force to turn clockwise. As the bent portion 6a, however, engages with the side face of the printing head 3, the operating lever 6 cannot be turned clockwise. Consequently, said clockwise force works as a force to turn the printing head 3 counterclockwise resisting against tension of the spring 5. Thus, the printing head 3 is brought to the condition that the printing portion 3a is pushed against the platen through the printing paper when the pin 8 reaches the high portion 10a of the cam surface 10A. This pushed condition is kept as it is as far as the pin 8 is kept on the high portion 100 of the cam surface 10A during the rightward movement of the head base 2.

In the above-mentioned embodiment. the spring 5 is used for releasing the printing head 3 from the platen.

ing the printing head 3 against the platen when the printing portion is arranged, for example, on the side designated by symbol 3a of the printing head 3 and the related mechanism is modified so that said printing portion 30 faces the platen.

I claim:

1. A device for controlling the movement of a printing head comprising:

a printing head having a printing portion thereon and movable along a recording surface of a recording paper faced to said printing portion and also rotatable about an axis extending parallel to said recording surface between a first position with said printing portion contacting said recording surface and a second position with said printing portion removed from said recording surface.

an operating lever pivotably mounted on and engageable with said printing head,

a cam plate extending in parallel with said recording surface to engage said operating lever,

a first spring connected to said printing head and urging said printing head totsaid second position,

a second spring connected between said printing head and said operating lever and urging said operating lever to engage said printing head,

said cam plate having a slope portion at one end thereof engageable with said operating lever for moving said printing head against the bias of said first spring from said second position to said first position,

low portion at the other end thereof engageable with said operating lever for allowing said first spring to urge said printing head to said second position from said first position, and

' high portion between said slope and low portions for maintaining said printing head in said first position when said printing head is moved along said recording surface in one direction in order to carry out printing and for maintaining said printing head in said second position when said printing head is moved in the opposition direction. 

1. A device for controlling the movement of a printing head comprising: a printing head having a printing portion thereon and movable along a recording surface of a recording paper faced to said printing portion and also rotatable about an axis extending parallel to said recording surface between a first position with said printing portion contacting said recording surface and a second position with said printing portion removed from said recording surface, an operating lever pivotably mounted on and engageable with said printing head, a cam plate extending in parallel with said recording surface to engage said operating lever, a first spring connected to said printing head and urging said printing head to said second position, a second spring connected between said printing head and said operating lever and urging said operating lever to engage said printing head, said cam plate having a slope portion at one end thereof engageable with said operating lever for moving said printing head against the bias of said first spring from second position to said first position, a low portion at the other end thereof engageable with said operating lever for allowing said first spring to urge said printing head to said second position from said first position, and a high portion between said slope and low portions for maintaining said printing head in said first position when said printing head is moved along said recording surface in one direction in order to carry out printing and for maintaining said printing head in said second position when said printing head is moved in the opposition direction. 